In an electronic apparatus such as the broadcasting transmission apparatus disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2008-22392, electronic circuit boards, each having a specific processing function, are removably connected to the free slots of the motherboard, respectively. On the motherboard, transmission paths are provided to transmit signals in differential mode between the electronic circuit boards inserted in the free slots.
As the speed of processing and transmitting signals increases in the electronic apparatus described above, the signal transmission distance between the circuit boards grows more important. The conventional motherboard having free slots is indeed advantageous in that each circuit board can be connected to any slot. However, the signal transmission distance between the boards is inevitably indefinite. Consequently, the transmission quality fails to be uniform, possibly resulting in transmission errors.
Particularly in any electronic circuit board, the parameters such as signal-amplitude level, drive current level and frequency-adjusting value, all enhancing the transmission quality, are fixed. The distance for which good transmission quality can be acquired between the boards is inevitably limited. This limits the number of slots that can be used at the electronic apparatus.